U.S. patent application number 12/190555 was filed with the patent office on 2010-02-18 for pressure sensor.
This patent application is currently assigned to ARGUS MACHINE CO. LTD.. Invention is credited to Brian Bruchal, William MacDonald, Jason Weiss.
Application Number | 20100037697 12/190555 |
Document ID | / |
Family ID | 41680334 |
Filed Date | 2010-02-18 |
United States Patent
Application |
20100037697 |
Kind Code |
A1 |
Weiss; Jason ; et
al. |
February 18, 2010 |
PRESSURE SENSOR
Abstract
An apparatus for sensing pressure is provided comprising a
housing, electronics, a pressure sensor and a secondary seal. The
housing comprises an interior bore and a first end, with the
interior bore forming an opening at the first end. The electronics
may be disposed in the interior bore. The pressure sensor is
mounted at the first end of the interior bore. The pressure sensor
may be operatively connected to send signals to the electronics in
response to external fluid pressure. The pressure sensor may, at
least in part, form a primary seal at the first end of the interior
bore. The secondary seal may be disposed in the interior bore in
between the pressure sensor and the electronics. The secondary seal
may be configured to act as a backup seal to the primary seal. The
secondary seal provides an added degree of safety from high
pressure pipeline contents. The secondary seal also ensures that
the important interior electrical components of the apparatus are
not damaged upon failure of any component located at the first end.
If the pressure sensor or primary seal is damaged, for example, a
new pressure sensor or primary seal may be installed without having
to replace the entire apparatus. The secondary seal also prevents
fluid from a high pressure pipeline that has compromised the
primary seal from being ejected from the pipeline. The secondary
seal also prevents pipeline media from migrating through the
electrical cable to a non-hazardous location.
Inventors: |
Weiss; Jason; (Edmonton,
CA) ; Bruchal; Brian; (Edmonton, CA) ;
MacDonald; William; (Edmonton, CA) |
Correspondence
Address: |
CHRISTENSEN, O'CONNOR, JOHNSON, KINDNESS, PLLC
1420 FIFTH AVENUE, SUITE 2800
SEATTLE
WA
98101-2347
US
|
Assignee: |
ARGUS MACHINE CO. LTD.
Edmonton
CA
|
Family ID: |
41680334 |
Appl. No.: |
12/190555 |
Filed: |
August 12, 2008 |
Current U.S.
Class: |
73/715 ;
73/756 |
Current CPC
Class: |
G01L 19/0672 20130101;
G01L 19/0084 20130101 |
Class at
Publication: |
73/715 ;
73/756 |
International
Class: |
G01L 7/08 20060101
G01L007/08 |
Claims
1. An apparatus for sensing pressure, comprising: a housing, the
housing comprising an interior bore and a first end, the interior
bore forming an opening at the first end; electronics disposed in
the interior bore; a pressure sensor mounted at the first end of
the interior bore, the pressure sensor operatively connected to
send signals to the electronics in response to external fluid
pressure, the pressure sensor at least in part forming a primary
seal at the first end of the interior bore; and a secondary seal
disposed in the interior bore between the pressure sensor and the
electronics, the secondary seal being a backup seal to the primary
seal.
2. The apparatus of claim 1 further comprising: a display
operatively connected to the electronics, the display being
configured to display data received from the electronics.
3. The apparatus of claim 2 wherein the display comprises a digital
display.
4. The apparatus of claim 1 wherein the electronics is configured
to send output signals corresponding to the external fluid
pressure.
5. The apparatus of claim 4 in which the output signals correspond
to the external pressure being outside of an adjustable range.
6. The apparatus of claim 1 wherein the pressure sensor comprises a
flexible diaphragm mounted at the first end of the interior bore,
and the flexible diaphragm forms at least part of the primary
seal.
7. The apparatus of claim 1 wherein the pressure sensor is
operatively connected to the electronics through conductive
paths.
8. The apparatus of claim 7 wherein the secondary seal comprises
potted material forming a seal around bare metal portions of the
conductive paths.
9. The apparatus of claim 8 wherein the conductive paths include a
junction between wires, the junction having a bare metal surface
around which potted material forms a seal.
10. An apparatus for sensing pressure, comprising: a housing, the
housing comprising an interior bore and a first end, the interior
bore forming an opening at the first end; electronics disposed in
the interior bore; a pressure sensor mounted at the first end of
the interior bore, the pressure sensor operatively connected to
send signals to the electronics in response to external fluid
pressure; a primary seal mounted at the first end of the interior
bore, the primary seal configured to prevent external fluids from
entering the interior bore; and a secondary seal disposed in the
interior bore between the pressure sensor and the electronics.
11. The apparatus of claim 10 further comprising: a display
operatively connected to the electronics, the display being
configured to display data received from the electronics.
12. The apparatus of claim 11 wherein the display comprises a
digital display.
13. The apparatus of claim 10 wherein the electronics is configured
to send output signals corresponding to the external fluid
pressure.
14. The apparatus of claim 13 in which the output signals
correspond to the external pressure being outside of an adjustable
range.
15. The apparatus of claim 10 wherein the pressure sensor comprises
a flexible diaphragm mounted on the first end of the interior
bore.
16. The apparatus of claim 10 wherein the pressure sensor is
operatively connected to the electronics through conductive
paths.
17. The apparatus of claim 16 wherein the secondary seal comprises
a potted seal around exposed portions of the conductive paths.
18. The apparatus of claim 17 wherein the exposed portions are
parts of a junction between wires forming the conductive paths.
Description
TECHNICAL FIELD
[0001] This document relates to pressure sensors.
BACKGROUND
[0002] U.S. Pat. No. 4,007,343 discloses a method and apparatus for
sensing fluid pressure. This device has a pressure gauge with a
digital readout, and a flexible diaphragm that responds to changing
pressure.
SUMMARY
[0003] An apparatus for sensing pressure is provided comprising a
housing, an electronics unit in the housing, a pressure sensor and
a secondary seal. The housing comprises an interior bore and a
first end, with the interior bore forming an opening at the first
end. The electronics unit may be disposed in the interior bore. The
pressure sensor is mounted at the first end of the interior bore.
The pressure sensor is operatively connected to send signals to the
electronics unit in response to external fluid pressure. The
pressure sensor, at least in part, forms a primary seal at the
first end of the interior bore. The secondary seal is disposed in
the interior bore in between the pressure sensor and the
electronics. The secondary seal acts as a backup seal to the
primary seal.
[0004] These and other aspects of the device and method are set out
in the claims, which are incorporated here by reference.
BRIEF DESCRIPTION OF THE FIGURES
[0005] Embodiments will now be described with reference to the
figures, in which like reference characters denote like elements,
by way of example, and in which:
[0006] FIG. 1 is a side elevation view of a pressure sensor.
[0007] FIG. 2 is a side elevation view, partially in section of the
pressure sensor of FIG. 1.
[0008] FIG. 3 is a side elevation view, in section, of the
secondary seal of the pressure sensor of FIG. 1.
[0009] FIG. 4 is a top plan view of the secondary seal shown in
FIG. 3.
[0010] FIGS. 5A-5B are side elevation views, in section, of a
junction of the secondary seal of FIG. 3.
[0011] FIG. 5C is a perspective view, partially in section, of a
further junction of the secondary seal of FIG. 3 illustrating six
wires.
DETAILED DESCRIPTION
[0012] A device connected to a fluid conduit to measure properties
of hazardous fluids contained within the fluid conduit may pose
safety problems if they are not properly sealed and protected.
Sometimes the fluid media (gases usually) can migrate between the
conductor wires and insulating jacket on an electrical wire
communicating with such a device. This media can then travel the
entire length of the electrical wire into an area that is not
protected with "hazardous location" equipment (eg: an electrical
panel many feet away from the transmitter that does not require
Class 1, Division 1 protection).
[0013] Referring to FIG. 1, an apparatus for sensing pressure,
generally referred to by the reference numeral 10, is illustrated.
Referring to FIG. 2, apparatus 10 comprises a housing 12,
electronics unit 14 in the housing supported by plate 14A, a
pressure sensor 16, and a secondary seal 18. Housing 12 comprises
an interior bore 20 and a first end 22. The housing 12 is formed of
two parts in this example, an electronics housing 12A and a
pressure sensor housing 12B that are threaded together with a seal
13 between them external to the threads. Interior bore 20 forms an
opening 24 at first end 22. The electronics housing 12A is capped
by end cap 20A through which connections to an external device are
made in conventional fashion. The electronics unit 14 is disposed
in interior bore 20. Pressure sensor 16 may be mounted at first end
22 of interior bore 20, pressure sensor 16 being operatively
connected to send signals to electronics 14 in response to external
fluid pressure. Electronics unit 14, for example, is configured to
send output signals corresponding to the external fluid pressure.
For example, the output signal may continually send external fluid
pressure data. In other embodiments, the output signal corresponds
to the external fluid pressure being outside of an adjustable
range. For example, if the external fluid pressure is above an
upper limit of the adjustable range, or below a lower limit of the
adjustable range, an output signal will be sent. The output signal
may be, for example, an electrical or wireless signal. In other
embodiments, the output signal may contain data that corresponds to
characteristics of the external fluid. For example, the output
signal may contain temperature or pressure readings.
[0014] Referring to FIG. 2, in one embodiment electronics unit 14
may comprise various pieces of standard electronic equipment,
including for example a microprocessor, an A/D converter, a display
driver, a power converter, an output driver, and/or a battery. The
microprocessor is used, for example, to perform calculations,
interpret signal data, and control the various components of
electronics 14. The A/D converter is provided for converting analog
signals into digital signals, and vice versa. The display driver is
provided to control a display 42 that is held in an opening of the
electronics housing 12A by a threaded sleeve 42A. The power
converter is provided for converting the input voltage from either
the battery or a wall outlet into a suitable voltage to be used by
apparatus 10. The output driver is provided to convert the digital
pressure signal into a useable output signal to control equipment
(not shown) to which the pressure sensor 10 is electrically
attached.
[0015] Pressure sensor 16 may form, at least in part, a primary
seal at first end 22 of interior bore 20. The primary seal is
configured to prevent external fluids from entering interior bore
20. In some embodiments, pressure sensor 16 may comprise a flexible
diaphragm 26 mounted at first end 22 of interior bore 20. Flexible
diaphragm 26 may form at least part of the primary seal. In further
embodiments, the primary seal may be provided distinct from
pressure sensor 16. The primary seal may be mounted at first end 22
of interior bore 20, the primary seal configured to prevent
external fluids from entering interior bore 20.
[0016] Referring to FIG. 2, secondary seal 18 is disposed in
interior bore 20 in between pressure sensor 16 and electronics unit
14. Secondary seal 18 acts as a backup seal to the primary seal.
Pressure sensor 16 is operatively connected to electronics unit 14
through conductive paths 28. The secondary seal 18 is formed within
a seal housing 19 that is sealed to a neck of the electronics
housing 12A by an O-ring seal 21. The secondary seal 18 is held in
place by pressure between a shoulder 25 on the neck of the
electronics housing 12A and threaded sleeve 23 that is threaded
into the pressure sensor housing 12B. Fasteners such as screws may
secure the sleeve 23 to the seal housing 19.
[0017] Referring to FIG. 2, secondary seal 18 may comprise potted
material forming a seal around exposed portions of conductive paths
28. The potted material may for example be a polyurethane but other
suitable electrically insulating and pressure resistant materials
may be used. Referring to FIG. 3, the seal may be in the form of a
potted seal 30 around conductive paths 28. Conductive paths 28 may
comprise a sensor end 32, with a connector 32A that is received by
a corresponding connector on the pressure sensor 16, and an
electronics end 34. with a connector 34A that plugs into a
corresponding connector on the electronics unit 14. Referring to
FIG. 3, potted seal 30 may comprise a sensor side 36 and an
electronics side 38. Referring to FIG. 2, sensor and electronics
sides 36 and 38, respectively, are oriented towards pressure sensor
16 and electronics unit 14, respectively. Referring to FIG. 3,
sensor end 32 enters secondary seal 18 from sensor side 36, while
electronics end 34 enters secondary seal 18 from electronics side
38. Sensor end 32 and electronics end 34 may be in electrical
communication with one another through at least one junction 40
disposed at least partly within potted seal 30.
[0018] Referring to FIG. 4, in some embodiments, conductive paths
28 may comprise three wires 54, each insulated by a respective
sheath 56. Referring to FIG. 5C, in some embodiments, conductive
paths 28 may comprise, for example, six wires 54. Referring to FIG.
4, in the embodiment shown, only three wires 54 are illustrated,
however the other three wires 54 may be positioned on the other
side (not shown) of insulated base 63. It should be understood that
any number of wires 54 are possible. The wires 54 of sensor and
electronics ends 32 and 34 are secured, as by soldering, to
respective first end 58 and second end 60 of metal connectors 59
forming junction 40. Potted material forms a dense seal around the
bare metal surface of junction 40, on all exposed sides, and
presses up against the metal of a central portion 61 of the metal
connectors 59 thus preventing any fluid that has managed to travel
up sheath 56 from passing through secondary seal 18. The metal
connectors 59 may be adhered to a circuit board or other insulated
base 63. The base 63 prevents fluid migration because the fluids
cannot span the base 63 and travel down the conductive paths
28.
[0019] Referring to FIG. 5A, central portions 61A of metal
connectors 59A may be lifted off a flat surface of insulated base
63. In embodiments where the metal connectors 59 are lifted off the
base 63, the potted material flows all around the connectors 59 to
provide the secondary seal. In embodiments where the metal
connectors 59, or at least their central portions 61, as
illustrated by metal connectors 59B with central portions 61B in
FIG. 5B, are part of or adhered to the base 63, the secondary seal
is provided by potted material abutting against the top and sides
of central portions 61B and the base 63, as well as the adhesion of
the central portion 61B to the base 63. Referring to FIG. 5C, metal
connectors 59 may be formed of conductive strips 59C with central
portions 61C sealed within or forming part of the insulated base
63. In another embodiment, the sheaths 56 of wires 54 may be
stripped off and the potted material adhered directly to the bare
wires 54. In this case, the metal connectors 59 forming the
junction 40 may not be necessary. A separator may be required to
keep the bare wires 54 from touching each other. In the embodiment
illustrated, only the top 3 wires 54 are illustrated by ghost
lines, although it should be understood that the bottom three wires
54 may be arranged in a similar, if not identical, fashion.
[0020] Referring to FIG. 2, display 42 may be operatively connected
to electronics unit 14 by conventional connector 43. Display 42 may
be configured to display data received from electronics unit 14. In
some embodiments, display 42 comprises a digital display.
[0021] Referring to FIG. 1, apparatus 10 may be installed on a
pipeline 44. Pipeline 44 may contain fluid 46, fluid 46 being at
least one of a gas or liquid. Housing 12 may be tightly installed
into an access conduit 48 of pipeline 44 using threading 50
adjacent first end 22. When installed, first end 22 may be in fluid
communication with the interior contents of pipeline 44. When in
use, the pressure from fluid 46 deflects pressure sensor 16. This
deflection may be measured by a strain gauge (not shown) affixed to
the inside of pressure sensor 16. In one embodiment, an exemplary
strain gauge may be arranged as a Wheatstone bridge circuit. The
strain gauge may deform under the pressure, and the deformation may
be converted into a signal. In some embodiments, this signal may
be, for example, generated by a change in electrical resistance
across the Wheatstone bridge. The signal is then transmitted as an
analog signal through conductive paths 28 to electronics unit 14.
The signal is converted into a digital signal by electronics unit
14. The digital signal may then be converted into a pressure value
and displayed. The pressure value may correspond to the pressure of
fluid 46 within pipeline 44 (as shown in FIG. 1). Electronics unit
14 may send the pressure value to display 42, where it may be
displayed. In some embodiments, the pressure value may be provided,
for example, in pounds per square inch or kilopascals. In further
embodiments, the pressure value may be transmitted for remote
monitoring for example, as a 4-20 mA signal. Control of the
adjustable range may be accomplished by manual or remote
programming of relays on electronics unit 14. When the pressure of
fluid 46 is detected as being outside the adjustable range, the
output signal is sent. The output signal may actuate an alarm, or
may be transmitted to equipment that may control the pressure of
fluid 46 within pipeline 44. An example may include an emergency
pipeline shutdown device.
[0022] Referring to FIG. 2, in some embodiments, housing 12 may be
made up of multiple pieces. In some embodiments, housing 12 may
comprise a removable component 52 at first end 22. Removable
component 52 may house pressure sensor 16. Removable component 52
may be replaced in the event of the failure of, for example,
pressure sensor 16 and/or the primary seal.
[0023] Secondary seal 18 provides an added degree of safety from
high pressure pipeline contents. Secondary seal 18 also prevents
pipeline contents from migrating out of the conduit system, for
example through the electrical cable. Secondary seal 18 also
ensures that the important interior electrical components, for
example electronics unit 14, of apparatus 10 are not damaged upon
failure of any component located at first end 22. If pressure
sensor 26 or the primary seal is damaged, for example, a new
pressure sensor 16 or primary seal may be installed without having
to replace the entirety of apparatus 10. Secondary seal 18 also
prevents fluid from a high pressure pipeline that has compromised
the primary seal from being ejected from the pipeline.
[0024] In the claims, the word "comprising" is used in its
inclusive sense and does not exclude other elements being present.
The indefinite article "a" before a claim feature does not exclude
more than one of the feature being present. Each one of the
individual features described here may be used in one or more
embodiments and is not, by virtue only of being described here, to
be construed as essential to all embodiments as defined by the
claims. Immaterial modifications may be made to the embodiments
described here without departing from what is covered by the
claims.
* * * * *